A circuit arrangement which includes at least one component in chip form, which requires cooling, as is disclosed for example in DE 35 08 456 C2, has at least one mounting plate on which the at least one chip-form component to be cooled is disposed. The mounting plate also carries contact surfaces which are connected by means of suitable connecting elements to the respective chip-form component. The mounting plate is disposed on a cooling member, and a pressing arrangement is operable to press the mounting plate against the cooling member. The mounting plate on which the chip-form component is disposed is glued into a housing and the pressing arrangement is formed by adjusting screws and intermediate portions. The adjusting screws are screwed through reinforcement portions of the housing. With such a design configuration, in particular when the circuit arrangement is subjected to a thermal loading which occurs over a prolonged period of time, it is not possible reliably to guarantee that the contact pressure of the pressing arrangement is maintained constant because the plastic material constituting the housing may suffer from a yield phenomenon, caused for example by a flow or creep effect on the part of the plastic material of the housing. Likewise, a loss of contact pressure may occur as a result of mechanical tolerances in regard to the non-flexible intermediate portions of the pressing arrangement.
DE 29 42 401 A1 discloses a semiconductor component with a pressing arrangement which has at least one assembly element which is stable in respect of shape and in relation to heat, in the form of a yoke arrangement, and a plate spring constituting an elastically yielding pressing means disposed on the inward side of the mounting element which is towards the cooling member which in turn is in the form of a trough-shaped element. The pressing means presses against the at least one component to be cooled and/or against the at least one mounting plate, in electrically insulated relationship, in the vicinity of the at least one component to be cooled. The use of a plate spring as part of the yielding pressure means provides that the contact pressure can be suitably set and kept at a substantially constant value.
JP 1 310 566 A (Patent Abstracts of Japan, E-879, 1990, Vol 14, No 112) discloses a semiconductor device with a yielding pressing means in the form of a spring disposed between a semiconductor chip and a cap.
JP 63-226952 A (Patent Abstracts of Japan, E-705, 1989, Vol 13, No 23) discloses a semiconductor device with a yielding pressing means in the form of a spring, wherein the spring does not press directly on to a semiconductor chip but presses against the semiconductor chip indirectly by way of an insulating material which covers the semiconductor chip.
DE 36 28 556 C1 describes a circuit or semiconductor arrangement in which at least one chip-form component to be cooled is disposed on a mounting plate and encapsulated in an insulating material. Current conductor portions of the chip-form component to be cooled are arranged at least at a number of locations as contact portions for pressure contacting purposes. The current conductor portions project from the encapsulation of insulating material, on the side of the component which is remote from the mounting plate. That circuit arrangement has a cooling member and a contact plate, with the contact portions being disposed on the mounting plate separately from the component to be cooled. Pressure contacting in respect of the contact portions occurs outside the insulating encapsulation and the contact plate is common to all the contact portions.
A power semiconductor module comprising a mounting plate which is metallised on both sides and which on the top side is fitted with components, fitted into a plastic housing and covered with casting material, is disclosed in DE 35 21 572 A1. In the module, at least one support is disposed on the mounting member or a component, an elastomeric casting is provided as a first soft casting material, with an upper portion of the support or supports projecting therefrom, while a thermosetting casting is provided as a second hard casting material, for covering the upper portion of the at least one support and connecting it to the housing.